Executors: When duty and personal interests conflict

A topic of considerable debate and some confusion amongst practitioners is how to advise their clients when they are named an executor in a will and they may have some claim on the estate or some other issue which may cause their personal interests to conflict with their duty as executor. Should the executor take up the appointment to administer the estate or should they renounce? Should beneficiaries take action to pass them over or have them removed? How can you protect your executor or trustee client?